8th International Symposium on High Temperature Metallurgical Processing: Utilization of Complex Ores
Sponsored by: TMS Extraction and Processing Division, TMS: Pyrometallurgy Committee
Program Organizers: Jiann-Yang Hwang, Michigan Technological University; Tao Jiang, Central South University; Mark Kennedy, Proval Partners SA; Onuralp Yücel, ITU; P. Chris Pistorius, Carnegie Mellon University; Varadarajan Seshadri, Universidade Federal de Minas Gerais; Baojun Zhao, The University of Queensland; Dean Gregurek, RHI AG; Ender Keskinkilic, Atilim University

Thursday 2:00 PM
March 2, 2017
Room: 18
Location: San Diego Convention Ctr

Session Chair: Tao Jiang, Central South University; Hongxu Li, University of Science and Technology Beijing

2:00 PM Introductory Comments

2:05 PM  
Intensification of Gold Leaching from a Multi-refractory Gold Concentrate by the Two-stage Roasting-alkaline Sulfide Washing-cyanidation Process: Li Qian1; Zhang Yan1; Li Xishan1; Xu Bin1; Yang Yong-bin1; Jiang Tao1; Li Hong-wei1; 1Central South University
    The cyanide leaching rate of gold from a multi-refractory gold concentrate (18.05g/t Au) containing 1.62% As, 20.76% S, 6.95% C and 1.31% Sb was only 1.33%. The enhancement of gold leaching was studied mainly by the pretreatment of oxidation roasting and alkaline sulfide washing. Results showed that after the two-stage roasting (i.e., I stage of 500℃, 1h and II stage of 700℃, 2h) most of sulfur (93.84%) and carbon (98.27%) were removed, but the gold leaching rate of calcine just reached 71.33% because the residual arsenic (0.63%) and antimony (1.15%) in calcine were still high. After alkaline sulfide solutions of mixed NaOH and Na2S washing, the residual arsenic and antimony was further decreased to 0.21% and 0.65%, respectively. Finally, after the conventional cyanide leaching, the gold leaching rate increased to 93.52% substantially. Also, the optimized particle size, NaCN concentration and leaching time were -0.045mm over 85%, 0.1% and 36h, respectively.

2:25 PM  
Evolution of Cr and Fe Species during Carbothermic Reduction of Chromite Ores: Dogan Paktunc1; Dawei Yu1; Samira Sokhanvaran1; Yves Thibault1; 1CANMET
    Reducibility of several different types of chromite ores from the Ring of Fire area of northern Ontario, Canada were studied at high temperatures by graphite with the addition of several catalysts/accelerants. The experiments were performed in both sealed tube furnaces and a thermogravimetric analyzer (TGA) under Ar atmosphere with continuous gas analysis. The products formed during carbothermic reduction were characterized by X-ray diffraction, optical microscopy, scanning electron microscopy, electron probe microanalysis and, at the molecular-scale, by synchrotron-based X-ray techniques. X-ray absorption near edge spectra (XANES) and extended X-ray absorption fine structure spectra (EXAFS) collected at Cr- and Fe-edges indicate various degrees of reduction and metallization with Fe reduction is always preceding that of Cr. The observations are supplemented by the thermodynamic simulations performed using FactSage. The quantitative distribution of the compounds, their nature and the phase transformations taking place during carbothermic direct reduction will be presented and discussed.

2:45 PM  
Phase Transformation of High Calcium Type Tin, Iron-bearing Tailings during Magnetizing Roasting Process: Zijian Su1; Yuanbo Zhang1; Yingming Chen1; Bingbing Liu1; Guanghui Li1; Tao Jiang1; 1Central South University
    High calcium type tin, iron-bearing tailing is recognized as one of typically complex iron ore resources in China. A process of magnetizing roasting process followed by magnetic separation was used to utilize the tailings in our previous paper. Under the optimal conditions, qualified magnetic concentrates were obtained and could be used for direct reduced iron production. In this study, the phase transformation of these tailings during the magnetizing roasting process was investigated. And the reaction behavior between calcium oxide and iron oxide was revealed by using XRD, TG-DSC, VSM, etc. The results indicated that calcium ferrite was easily formed under CO-CO2 atmosphere, which has an unfavorable effect on the separation of iron and tin oxides from the tailings.

3:05 PM  
Roasting of Celestite in Laboratory Scale Rotary Furnace: Selim Ertürk1; Rasit Sezer2; Goksel Hizli1; Aysegul Bilen1; Cuneyt Arslan1; 1Istanbul Technical University; 2Karadeniz Technical University
    Turkish celestite is roasted in a lab scale rotary kiln furnace with metallurgical coke. Coke and the celestite is mixed as the product contains 32% coke which is excess than stoichiometry. 100 g of the mixed product is fed to the furnace with a 35 g/min rate. Temperature (1000 and 1100°C), rotating speed (2.5, 5 and 10 rpm), slope of the furnace (2, 3 and 5°) were the investigated parameters. Phase analyses were done by XRD, chemical analyses were done by XRF and AAS methods.The maximum solubility in water of the roasted product is 48.25% at roasting conditions of 1100°C, 2.5 rpm and 2° slope.

3:25 PM Break

3:45 PM  
The Experimental Study of CaCO3 in the Vanadium Extraction Process: Shu-Chao Wang1; Yu Wang1; Wei-tong Du1; Peng-cheng Li1; 1Chongqing University
     In this experiment, the main research based on the content of CO2 is 10 percent adding different CaCO3 quality. The result dedicates that adding CaCO3 on vanadium extraction process has no obvious effect on the oxidation of carbon, but has partly increased the vanadium oxidation rate of which the has rate reached more than 90% in the process of vanadium extraction. Meanwhile, along with the increase of the content of CaCO3, the capability of CaCO3 of the cooling the molten pooled also has been enhanced, which can reduce, at maximum,molten pool's temperature by 20 degrees in this experiment. In addition, the oxidation rate of P also has increased with the highest rate reaching to 40%. The research has proved that the application of CacO3 on vanadium oxidation process for the oxidation of V and P is effective.

4:05 PM  
Effect of Reduced Flux Iron Ore Pellets on Removal of Sulfur and Phosphorous in Single Step by Plasma and Induction Melting: Raj Dishwar1; Arup Kumar Mandal1; Shavi Agrawal1; Om Prakash Sinha1; Girija Shankar Mahobia1; 1Indian Institute of Technology, BHU
     During the mining a lot of iron ore fines (~60%) generated. For the utilization of these iron ore fines and waste lime fines we adopted a new method for making fluxed pellets. Main objective of the present work is to remove phosphorous and sulfur in single step by using reduced fluxed pellets during melting and refining of pig iron and steel. By using these reduced fluxed pellets (>80%) in pig iron melt in different melting conditions (i.e. plasma and induction melting), in which phosphorous (72.93%) and sulfur (85.23%) were removed in single step during induction melting route.

4:25 PM  
The Extraction of Zinc from Zinc Ferrite by Calcified Roasting and Ammonia Leaching Process: Zeqiang Xie1; Yufeng Guo1; Tao Jiang1; Feng Chen1; Lingzhi Yang1; 1Central South University, School of Minerals Processing and Bioengineering
    Zinc ferrite (ZnFe2O4), one of the major forms of zinc in Electric Arc Furnace (EAF) dust and zinc leaching residue, is very difficult to chemically dissolve in either acidic or alkaline solutions. In spite of the zinc resources in the Electric Arc Furnace (EAF) dust and zinc leaching residue are abundant, there is no mature utilization technology. This situation not only cause the waste of resources, but also produce the harm to the environment. In the paper, the basic principle of this process has been established by revealing the phase equilibria in the CaO–Fe2O3–ZnO system, where Ca2Fe2O5 can be in equilibrium with ZnO rather than ZnFe2O4 at higher CaO region. It has also been demonstrated that the formed ZnO can be solved by ammonia-leaching and Ca2Fe2O5 keep in solid residue, which can be used as a flux for steel refining.

4:45 PM  
The Recovery of Cobalt from Copper Converter Slag by Reduction-sulfurization Smelting at High Temperature: Shi Sun1; Hongxu Li1; Jiaqi Fan1; Chao Li1; Qi Liu1; Zhaobo Liu2; 1University of Science and Technology Beijing; 2University of Science & Technology Beijing
    With the great demand of consumer electronics (CE) and electric vehicles (EV), cobalt become one of the more scarce energy metals. The recovery of cobalt from a copper converter slag, which contained over 2.4% Co and were piled up as Industrial waste, by reduction-sulfurization smelting was explored. Quantitative analysis of treated slag showed that activated carbon and ferrous sulfide can be used to settle cobalt into matte as Co-Fe alloy. The experiment was carried on at 1673K with a reducing atmosphere of burning electrode graphite crucible. It was found that increasing the amount of activated carbon could get obvious growth trend of recovery rate of Co and ferrous sulfide got horizontal trend. Over 95% Co, 99%Cu and 62% Fe were settled into matte and phases of Co-Fe and Cu were different. Preliminary separation of Co from converter slag by pyrometallurgical smelting is proposed.